A scheduling algorithm for open pit mines

An open pit (opencast) mine can be described by a three-dimensionalarray of blocks, each of which is assigned a number of valuesdefining its characteristics. Scheduling an open pit consistsin finding a sequence in which the blocks should be removedfrom the mine in order to maximize the total discounted profitfrom the mine subject to a variety of technical and economicconstraints. This paper proposes to model the mine-schedulingproblem as one of sequential optimization, and develops an algorithmfor its solution. To overcome the difficulty caused by an extremelylarge number of states in the problem at hand, we consider atechnique which is related to dynamic programming but avoidsthe complete enumeration of the state space. Our algorithm isa combination of this technique with powerful heuristics derivedfrom the specific properties of open pit mining.